This invention relates to containers for bulk contents, and more particularly to a container made of paperboard and including a novel window which provides visibility into the container for indicating the level and/or content of the container.
Liquid containers with liquid level indicating windows have been provided heretofore. However, they are characterized by requiring complex and costly structural configurations to be incorporated in the container to secure correspondingly complex and costly window structures. Typical of these are disclosed in U.S. Pat. Nos. 292,532; 420,781; 2,172,864; 3,205,764; 4,363,240 ; and 4,376,490.
U.S. Pat. Nos. 3,017,987 discloses a container with transparent windows in which the container is molded of polyethylene having a thickness which renders it opaque, but with integral window portions molded to a thinner cross section which renders the windows transparent. The sizes and shapes of the containers are limited by the practical costs and dimensional limitations of the plastic molding dies.